1. Technical Field
The present invention relates to an ion implantation method, a carrier, and an ion implantation device.
2. Description of the Related Art
A solar cell is configured such that electron-hole pairs generated when a semiconductor material such as silicon absorbs light are subject to an electric field of the pn-junction formed in the solar cell so that electrons move to the n-type layer and protons move to the p-type layer and an electric current is retrieved in an external circuit accordingly. For formation of a pn-junction and a contact layer, it is necessary to process the material so that the concentration and type of impurities differ from one place to another. Ion implantation is used in such a process.
For example, there is known a device adapted to implant ions on the surface of a substrate multiple time in order to produce an impurity profile that improves the efficiency of a solar cell. In the first step, the device is evacuated and ions are implanted in the substrate. This is followed by placement of a mask on the substrate inside the device. The second step of ion implantation is subsequently performed.